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(ModeL) 2 Sheets-Sheet 1.

R.'T. SITTERLEY.

TIME AND INTEREST INDICATOR.

Patented July 21, 1885.

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N4 PETERS, PhmwLinm n hor. Walhlngtcn.

(Model.) 2 Sheets-Sheet 2.

R. T. SITTERLEY TIME AND INTEREST INDICATOR.

No. 322,757. Patented July 21, 1885.

$5 3K; By

N. PETERS. Pnaw-umogn har. Washington. 0. c.

UNITED STATES.

PATENT OFFICE.

REUBEN T. SITTERLEY, OF OABTHAGE, MIssOUEI.

TIME AND INTEREST INDICATOR.

I SPECIFICATION forming part of Letters Patent No. 322,757, dated July21, 1885.

Application filed January 14, 1884. (ModeL) To all whom, it may concern:

Be it known that I, REUBEN T. SITTERLEY, of Carthage, in the county ofJasper and State of Missouri, have invented a new and useful Improvementin Time and Interest Indicators, which improvement is fully set forth inthe following specification and accompanying drawings, in which Figure 1is a face view of my improved time and interest indicator. Fig. 2 is adiametrical section of the same. Fig. 3 is an enlarged view of a sector,showing the manner in which the indicator is used.

The object of my invention is to provide a calendar which computes theinterest at any per cent. and for any portion of time. In ad dition towhich the device indicates the number of days or weeks prior to or aftera given time, as well as afiords a'ready means of ascertaining the dayupon which the 1st of J an uary of any year falls, or of any other dayof the year, as will appear from the following description.

The device consists of a large disk,which is secured centrally to thespindle of a knob or handle on the under side of the disk. Upon thisdisk is placed a secondv one, smaller in diameter than the first, andadapted to be rotated on the spindle. A thin and flat straightedge isalso pivoted loosely on the spindle, and is designed to be turned aroundon the faces of the two disks above referred to. A third disk, smallerthan the second, is then placed centrally on the spindle, and secured toit so that it will only rotate with the latter. A spur on thestraight-edge or rule extends partly over the smallest disk, so as toindicate the figures on the radial lines thereon. The faces of the disksand rule are suitably lettered and figured to properly show by the aidof the rule the figures desired in any calculation, all of which will benow more fully explained. The largest disk, A, and the smallest disk, 0,are rigidly secured to the spindle D. The middle disk, B, rotates freelyon the spindle. The rule or straight-edge E is free to be turned aroundthe said spindle, and one of its edges, E, is a true radial line fromthe axis of the spindle D. The rule is preferably placed between thedisks 0 and B, although it may be between the disks A and B. As shown inthis instance, a spur, F, extends over the face of the smallest disk, 0.The face of the disks have certain figures and letters thereon, which Iwill now explain, particular reference being had to Fig. 3, which isenlarged for clearly displaying the characters on the several disks andon the rule. The largest disk, A, has three hundred and sixty radiallines, G, forming spaces representing the three hundred and sixty daysof the twelve interest-months of thirty days each. It also has anumberof concentric lines, H, and there may be as many of these latter asdesirable, so as to permit of placing thereon from one to twelve figuresor more. The inner circle, I, on this disk has indicated on it the daysfrom one to three hundred and sixty, inclusive, and the figures in thespaces formed between the radial lines G and concentric lines IIindicate the interest.

It will be observed that the rule E has near its radial edge E a seriesof figures from 1 to 8, which represent the dollars on which interest isto be calculated.

By referring to the smallest disk, 0, it will be seen that the outercircular space, J, indicates. the day of the week, the next column,

K,the true time--that is, the day of the yearin contradistinction to thecolumn I, which gives interest time. Column L numbers the days of theweek successively, and column M gives the number of the week after orbefore a given time. The column M gives the names of the week-daysopposite the years in column N, while the last or inner column, N, givesthe successive years. This will indicate on what day the year came in.For instance, referring to 1876, it will be found that Sa is in the nextcolumn, indicating that January 1st, 1876, fell on Saturday. By thismeans the day of the month of any week-day can also be found. Thestarting-point in column I, showing interest time, is one day ahead ofthe true or calendar time as given in column K. The middle disk,B,hasthree circular divisions, the outer division, 0, having theinterest-days of the month from 1 to 30, inclusive, while the innerdivision, P, has the true number of days which occur in each month. Thename of the month is printed in the middle division, Q. Thus while boththe interest and true days are given side by side, no conflict can arisein computing the interest, or in finding the number of days, or inmaking any other calculation that is desired. Thus, for instance, shouldit be desired to find out how many days intervened between January 20and March 24, the middle disk, B, would be moved to the position shownin Fig. 3, with the figure 24 of March in column P opposite figure l incolumn K nearest the rule E. The rule is then turned so as to rest overthe figure 20 in column P of Januarygvhen the radial figure in column Kwill show the correct number, which is 63. The true number ofinterest-days, however, is sixty-four, as shown in column I, since bothJanuary and February must have thirty days, whereas by true time theyhave thirty-one and twenty-eight days, respectively, in ordinary years.

It will be noticed that the rule E has represented on it a series offigures from 10 to 400 radially,and from 10 to 50 concentrically. Thesefigures show the interest-calculations for even years, and forconvenience they are placed on the rule. Thus, as shown in Fig. 3, ifthe ob- 2 ject is to find the interest of seven dollars at ten per cent.for one year and seventy-eight days,the first column on the rule Enearest the edge E of the rule, 7, in the dollar column gives cents asinterest for one year, and then by placing the rule so that its edge Eshall bejust to the left of 78 on the inner circular column, H, on thedisk A the figuresin the outer concentric row on this disk A which comenearest 7 give 15 cents for the 7 8 days.

While this drawing only shows calculations of interest on sums of fivedollars and less, it will be obvious that the principle above clearlyexplained can be applied to any sums which can be entered on the rule E.In practice I design to make this adapted for $1,000.

As shown in the drawings, the calculations ,are made on the basis of tenper centum per annum; but I do not confine myself to this per cent. Ifind it is much more convenient to compute the interest at this percent. and then multiply the result so obtained by the per cent. desired,when, by striking off the righthand figure of the product, the correctresult is ascertained.

I am aware that interest and time calculating disks and pointers havebeen used before the within-described device, and I do not, broadly,claim such devices.

Having described my invention, I claim- 1. An interest and timecalculating device consisting of the fixed disks A and O, theintermediate disk, B, and the movable rule E, having characters on them,as shown and described, in combination with the central spindle,substantially as specified.

2. The combination of the central spindle, D, the disks A and O fixedthereto, the disk B, and rule E movable thereon, and a spur, F, on ruleE, all substantially as and for the purposes described.

3. A time and interest indicator comprising a disk, A, fixed on aspindle, D, and having radial lines representing twelve months of thirtydays, concentric lines leaving space on which are figures representingdollars, and an inner circle having figures representing days i from oneto three hundred and sixty and interest time, and spaces indicatinginterest, a movable rule, E, having columns of figures representingdollars on which interest is to be calculated, a fixed disk, 0, havingan outer circular space indicating days of the week, a space indicatingtrue time, a circular space indicating the number of days of the week, aspace giving the number of the week after or before a given time, also aspace giving the successive years, and a middle movable disk, 13, havingthree circular divisions, the outer division, 0, showing interest-daysofthe month, an inner division, P, showing true number of days in eachmonth, and an intermediate division showing the names of the month, allas herein described and shown.

In testimony that I claim the foregoing I have hereunto set my hand,this 8th day of November, 1883, in the presence of witnesses.

REUBEN T. SITTERLEY.

WVi tn esses J. S. ZERBE, O. J. BAILEY.

